Extremely simplified. Do not assume these are perfect definitions. This is what I would use to describe a network to my parents or someone else that is only concerned about consumer use.

The goal of this is so that I can explain something to you, and you can at least get the gist of what I'm saying without me having to explain each and every technical term.

ISP

Internet Service Provider. AT&T, Comcast, etc. Usually provided by

DSL

Cable

Dial-up

Satellite

Cell towers(3G/4G/LTE)

Fiber

Infrastructure

This usually refers to your ISP's infrastructure from a location they own to your home. If you have DSL and a phone line got cut on the way to your house, you could say that's an infrastructure problem, kinda.

Public IP Address

This is basically your network's "address" to the world. Most ISPs provide you with one IP address for your network, though it's possible to have more than one.

TCP/IP/UDP Ports

A port is basically a "channel" that communications happen between two IP addresses. If your IP address is your "Address" on the internet, the port number they use is the "PO Box".

LAN

Local Area Network. This is your local network. The public internet can not see this network unless you explicitly share it with them.

WAN

Wide Area Network. This is the internet. A "WAN port" is a port which connects directly to the internet (ie, to your ISP's routers and other equipment)

Modem

A modem is a device which takes an encoded connection from an upstream provider(your ISP) and decodes it so you can easily communicate with it from your standard ethernet network. Most modern modems have built in routers so that you can have an "all-in-one" device that creates a usable network.

Router

A router is a lot of thing. It's primary purpose is to share your public IP address among more than one device with a method called NAT. Most routers also have a built in switch so that you can easily hook up more than one computer to the router, though technically a router could function with just a WAN and a LAN port. Routers usually handle NAT and firewalls.

NAT

NAT stands for Network Address Translation. This is the process used by routers to take your 1 public IP address and let as many computers as you want to use the internet behind it. Without NAT, you'd be limited to one device using the internet at a time without paying for more public IP addresses

Switch/Hub

A switch is basically the same as a hub, as far as you are probably concerned. A switch works as a "repeater" so that you can connect multiple devices to a single router. Without switches, your router could only connect to 1 computer. A switch is not a router. A router handles NAT and firewalls to allow you to share a single connection among different computers. A switch just makes it so that multiple computers can "connect" to that single core connection

Firewall

A firewall WILL NOT protect your computer from viruses, at least not with modern networks. A firewall prevents the internet from touching your private network(LAN). With NAT, a firewall is required because of how NAT works.

Port forwarding

Port forwarding is the process by which you selectively allow a certain device on your network to be reached from the internet. This is basically making a "pinhole" in your Firewall to allow the internet to go to a certain device using a certain port.

Wifi

This is a wireless technology which can replace traditional ethernet cables. If you have a modem and router(without wifi), to enable wifi on your network you must buy a wireless switch. It's just like a switch(lets multiple computers connect to your single connection), except for it's wireless instead of wired

802.11b

This is the early verion of Wifi. It's slow, but not usually slower than your internet connection. (it's usually not the bottleneck)

802.11g

This is not the newest version of Wifi, but it's not bad. It's fairly fast and it will be fairly rare that it is slower than your internet connection.

802.11n

This is the newest standard and is blazing fast. If you have an internet connection that is faster than this protocol allows, you probably don't need to be taught these terms

Wireless Speeds

This isn't a term, but wireless speed usually is limited by either your connecting device(ie, smartphone, laptop, etc) or your wireless modem/router/switch. If your have an 802.11n wireless switch, but your smartphone only supports 802.11g, they can still talk to each other, but it won't be at 802.11n speeds.

NAS

Network Attached Storage. This is a device such as a harddrive that is connected to your private network(LAN). This allows you to access this harddrive from any device on your network. These make great backup systems. If you have one of these and use Wifi, you'll want to use 802.11n when possible

DNS Server

Domain Name System Server. This is the server which looks up "names" on the internet. For instance, you type "google.com" in your browser, the internet doesn't know where "google.com" is, it only understands IP addresses. So, it asks a DNS server "who the hell is google.com?" and the DNS server replies with "here's google's IP address"

IPv4

This is the "old" IP address system. There are less than 4 billion addresses available, and we are approaching that limit. As such, IP addresses are getting scarce.

IPv6

This is a huge topic, but basically all you need to know is it's the "new" IP address system. We are currently running out of IPv4 addresses because there are less than 4 billion available for use. We obviously are approaching that many devices on the internet and as such, they are becoming scarce. IPv6 increases this number so that you can have multiple public IP addresses to your network. IPv6 and IPv4 can't really "talk" to each other though. If you have an IPv6-only device, it can't talk to a website served using only IPv4.

It's the future, but it's not here yet, so it's best to have both IPv4 and IPv6 support at this point.

Internet Backbone

This is the "core" of the internet and consists of very high capacity routers owned by powerful companies. The backbone of the internet is provided by (for the most part) very fast fiber

Hopefully, you know enough to keep up moderately (get the "gist" of) when someone explains something about your network/internet now.